The use of X-rays for diagnostic purposes, and radiotherapy, expecially as applicable for treatment of malignancies, has been found necessary and desireable in many phases of dentistry and medicine.
Unnecessary and uncontrolled subjection of the human body, or portions thereof, to radiation, however, including X-rays for diagnostic purposes, or radiation exposure connected with radiotherapy treatment of malignancies, are increasingly recognized as being harmful.
The medical and dental professions accordingly have taken steps attempting to reduce, in so far as possible, the subjection of patients to such harmful radiation, occuring either inadvertently or during intended treatment but perhaps to specifically different parts of the body, or resulting from stray, scattered and surplus rays.
Recent studies have shown, for example, that oral complications occur in patients undergoing radiotherapy treatments for malignancies, even though the malignancies were not in the head and neck. An article in The Journal of the American Dental Association, September 1978, Volume 97, No. 3, pps. 468-472, by Stephen T. Sonis, Andrew L. Sonis and Alan Lieberman, entitled "Oral Complications in Patients Receiving Treatment for Malignancies Other Than of The Head and Neck" discusses the results of a recent study in this connection and reference is made therein to several additional publications & articles reporting the results of other studies. The following ones of the articles are pertinent in regard to the background of the present invention:
Ref. 1. DelRegato, J.A. Dental lesions observed after roentgen therapy in cancer of the buccal cavity, pharynx, and larynx. American Journal of Roentgenology Radium Therapy and Nuclear Medicine, 42:404, Sept. 1939.
Ref. 2 King, E.R., Elzay, R.P. and Dettman, P.M., Effects of ionizing radiation in the human oral cavity and oropharynx, results of a survey. Radiology, 91:990, November 1968.
The use of X-rays for diagnostic purposes in dentistry has also recently been of some concern. Research has generally led the medical and dental professions to avoid unnecessary exposure of patients to X-rays.
It has been found that even very limited amounts of exposure to radiation, especially in children, sometimes causes damage to such glands as the pituitary and thyroid. In efforts to avoid such problems, techniques and apparatus have been developed attempting to either absorb or otherwise shield body areas of a patient from undesired exposure or from stray, or scattered x-rays such as those which normally tend to scatter from the principal stream of X-rays. Preferably the only X-rays allowed to contact human tissue are those necessary in the procedure. Some apparatus of this type is disclosed, for example, in United States Patents Re. 25,773; 3,304,422 and 3,304,423. These patents disclose dental X-ray shields and X-ray aiming means, in conjunction with X-ray film holding devices used in the taking of X-rays of teeth. The stated purpose, and suggested result, is to greatly minimize possible injury to the patient from scattered and surplus X-rays contacting tissues other than those which are intended to be subjected to X-rays.
It is also known to use protective garments or covers, in the nature of aprons and the like, to shield patients and/or certain body areas from stray X-rays during the course of X-ray examination or treatment. An example of an apron type of protective shield is shown in U.S. Pat. No. 3,233,248. Generally, however, such shields and/or protective covers are very heavy and uncomfortable, and varied sizes are required for efficient use with different individual patients.
Another example of a protective shield is shown in U.S. Pat. No. 3,569,713. This patent discloses a shield used in dentistry which is adapted for positionment on, and partially around, the neck of a patient, and is a shield for the thyroid gland of the patient.
There is additionally an increasing awareness in the medical and dental professions of possible serious damages which can be inflicted on teeth, gingiva, dentition, periodontal bone, parotid, sublingual, and salivary glands, and other related near body areas, by harmful side effects of radiation therapy, particularly when the patient receives large radiation doses in the head and neck regions for example.
Research, resulting in part in the above noted articles, which while alluding generally to detrimental and dangerous conditions resulting from negligent use of radiation, fail to completely appreciate the problems, and the techniques and apparatus advanced in the articles, as also in the prior patents, have failed to solve some of the existing problems.
A primary purpose of the present invention is to provide techniques and apparatus which help to overcome some of the existing problems, and to a very substantial extent fulfill a need in the medical and dental professions.